Twisted cable

ABSTRACT

A twisted cable includes a main body which includes a central filament and a plurality of twisted filaments. The twisted filaments are arranged around the central filament and include six first filaments, twelve second filaments, and eighteen third filaments from the central filament outward. The cross-section of each first filament is the same with the one of each second filament. The cross-section of each first filament is larger than the one of the third filament but smaller than the one of the central filament. The twisted filaments are twisted around the central filament. As a result, the twisted cable of the present invention has improved structure strength, appropriate toughness, and smaller amount of longitudinal deformation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cable, more especially to a cable for vehicles.

2. Description of the Prior Art

Metal cables or wires are widely used in brake systems of vehicles for triggering the brake clamp. Conventional metal cables are formed by twisting a plurality of filaments which are the same with each other, as shown in TW 227238, U.S. Pat. No. 6,119,747, and U.S. Pat. No. 6,405,774. However, the conventional cables are formed by less than 27 filaments so that structure strength is insufficient. In addition, the filaments are twisted staggeredly. Thus, when the cable is radially pressed inward, the filaments may be compressed and deformed.

During braking, the cable is pulled axially, so the tension may result radial deformation. As a result, the cable is lengthened to reduce accuracy of braking.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide a twisted cable having better structure strength and smaller amount of longitudinal deformation to transmit forces.

To achieve the above and other objects, a twisted cable of the present invention includes a main body. The main body includes a central filament and a plurality of twisted filaments wherein the twisted filaments are arranged around the central filament. The twisted filaments are classified into an inner layer, an intermediate layer, and an outer layer which are arranged outward. The twisted filaments include first filaments, second filaments, and third filaments. Cross-section area of each first filament is same with cross-section area of each second filament, and cross-section area of each third filament is smaller than the cross-section area of each first filament. The cross-section areas of each first filament, each second filament, and each third filament are smaller than cross-section area of the central filament respectively. The inner layer includes six first filaments. The intermediate layer includes twelve second filaments. The outer layer includes eighteen third filaments. The twisted filaments are twisted around the central filament.

Thereby, filaments of the present invention are arranged evenly, and appropriate gaps are kept between filaments. Thus, structure strength is promoted, and longitudinal tension can be transmitted evenly. As a result, accuracy may not be reduced due to the longitudinal deformation.

The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment(s) in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a stereogram of the present invention;

FIG. 2 is a stereogram showing a main body of the present invention;

FIG. 3 is a profile of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIG. 1 to FIG. 3, the twisted cable of the present invention includes main body 10. The main body 10 includes a central filament 11 and a plurality of twisted filaments wherein the twisted filaments are arranged around the central filament 11. The twisted filaments are sorted into an inner layer, an intermediate layer, and an outer layer outward from the central filament. Specifically, the twisted filaments include first filaments 12, second filaments 13, and third filaments 14. Cross-section area of each first filament 12 is the same with cross-section area of each second filament 13. Cross-section area of each third filament 14 is smaller than the cross-section area of the first filament 12. Any one of the cross-sections of each first filament 12, each second filament 13, and each third filament 14 is smaller than cross-section area of the central filament 11. The inner layer includes six first filaments 12. The intermediate layer includes twelve second filaments 13. The outer layer includes eighteen third filaments 14.

In the present embodiment, each of cross-sections of the central filament 11 and the twisted filaments is a circle, and the central filament 11 and the twisted filaments are all made of metal. Preferably, ratio of diameters of cross-sections of the central filament 11, each first filament 12, each second filament 13, and each third filament 14 is approximately 23:22:22:21. Practically, diameters of cross-sections of the central filament 11, each first filament 12, each second filament 13, and each third filament 14 are 0.23 mm, 0.22 mm, 0.22 mm, and 0.21 mm respectively. In a cross-section of the twisted cable, as shown in FIG. 3, the central filament 11, each first filament 12, one of the second filaments 13, and one of the third filaments 14 are aligned to be arranged in a straight line. That is, the central filament 11, two opposite first filaments 12, two opposite second filaments 13, and two opposite third filaments 14 are aligned. These seven filaments are aligned in a diameter of the twisted cable and abut each other one by one to form a connected structure. Thus, three connection structures are formed and are arranged equally to be crossed to each other at the central filament 11. As a result, a radial skeleton or framework having a center in the central filament is provided. The other second filaments 13 and the third filaments 14 are arranged evenly among the connected structures.

In the present invention, the radial connected structures help prevent the main body from radial compression. The second filaments and the third filaments which not belong to the connected structures are also prevented from radial compression due to the support of the connected structures. Thus, the main body is prevented from longitudinal and axial deformation. As a result, tension can be transmitted accurately, and controlling becomes easier. Besides, the second filaments and the third filaments among the connected structures can serve as cushions to provide bendability. 

What is claimed is:
 1. A twisted cable, including a main body, the main body including a central filament and a plurality of twisted filaments, the twisted filaments being arranged around the central filament, the twisted filaments being classified into an inner layer, an intermediate layer, and an outer layer which are arranged outward; wherein the twisted filaments includes first filaments, second filaments, and third filaments, cross-section area of each first filament is same with cross-section area of each second filament, cross-section area of each third filament is smaller than the cross-section area of each first filament, the cross-section areas of each first filament, each second filament, and each third filament are smaller than cross-section area of the central filament respectively, the inner layer includes six first filaments, the intermediate layer includes twelve second filaments, the outer layer includes eighteen third filaments, the twisted filaments are twisted around the central filament.
 2. The twisted cable of claim 1, wherein the central filament, each first filament, one of the second filaments, and one of the third filaments are aligned in a cross-section of the twisted cable.
 3. The twisted cable of claim 1, wherein the cross-section of the central filament and the cross-section of each twisted cable are circles.
 4. The twisted cable of claim 3, wherein ratio of diameter of the central filament, each first filament, each second filament, and each third filament is 23:22:22:21.
 5. The twisted cable of claim 1, wherein the central filament and each twisted filament are made of metal. 